Removable Partial Dentures - Semmelweis Egyetem
Transcript of Removable Partial Dentures - Semmelweis Egyetem
Krisztina Marton
Removable Partial Dentures
Every denture: acrylic denture with wire clasp (spoon denture)
Designing Removable Partial Dentures
The Individual Parts of the RPD
1. Saddles
2. Occlusal rests and similar components
3. Direct retainers
4. Connectors
Saddles Replaces the lost alveolar tissues (flange) and carries
arteficial teeth (real saddle)
Types:
Bounded
Free end
Material of the fitting surface
Acrylic resin Disadvantageous to the health of the underlaying mucosa and
the gingival margin of the remaining teeth
Metal, or metal-acrylic combination Provides better health of the mucosa because of the metal’s
highly polished surface, acrylic can provide acceptable esthetics
Connectors of the RPD
Upper arch
Distributes load to the mucosa Butterfly
Horseshoe
Fenestrated
Sceletonized
Labial bar
Minor connectorsconnect small of the metal frame to the baseplate
Major connectorsconnect the two sides of the denture to eachother
• Lower arch– Not distributes load to the
mucosa• Lingual plate• ”finger type” lingual plate• Lingual bar• Lingual bar with continuous
clasp (Kennedy bar)• Sublingual bar• Dental plate• Labial (or buccal) bar
Lingual bar
Lower connectors
Lower connectors 2
Direct retainers of the RPD These provide resistance to movement of the denture
along the path of displacement and/or path of insertion and withdrawal during any function (hindering its removal of its supporting tissues
Types CLASPS
Retentive clasp arms (usually incorporated in clasp units)
PRECISION ATTACHEMENTS
Clasps As the denture is inserted, the flexible tip of the
retentive arm passes over the maximum bulbosity (the prosthetic equator) of a tooth and enters an undercut area.
Once the denture is fully seated, the clasp sits passively in its place , just contacting the tooth surface without forcing on it.
As the denture is subjected to displacing forces during function , the tip of the clasparm is drawn back towards the maximum bulbosity of the tooth . If the displacing forces do not exceed the level of lifting the clasp arm over the survey line the denture will stay in position
Clasp Types:
gingivally aproaching
occlusally aproachingMaterial:
Rigid: Cast metal (usually cast together with the baseplate) Gold alloys
Silver palladium alloys
Cobalt cromium alloys
Stainless steel
Titanium
Elastic: Wrought wire (later adapted to the flange) Gold
Stainless steel
clasparm
Clasp unit
Gingivally aproaching clasp
Occlusally aproaching clasp
Clasp unit